Electromagnetic apparatus



June 12, 1934. P. H. CRAGO 1,962,234

ELECTROMAGNETIC APPARATUS Filed Oct. 6, 1932 2 Sheets-Sheet 1 Permanent .50

J9 57% E59 1 556 l HIS ATTORNEY.

June 12, 1934;

P. H. CRAGO ELECTROMAGNETIC APPARATUS Filed Oct. 6, 1932 w 2 Sheets-Sheet 2 R H m@ m E m 6 M 8 Rm 3 Q I WY \.|-B F M w 1H m 1 g wm m w m/ E NW Q Rm 3 Patented June 12, 1934 UNITED STATES PATENT OFFICE ELECTROMAGNETIC APPARATUS Application October 6, 1932, Serial No. 636,475

2 Claims.

My invention relates to electromagnetic apparatus, and particularly to apparatus of the type involving a polarized electromagnetic device having a neutral armature and a polar armature.

One feature of my invention is the provision in apparatus of this character of means whereby the neutral armature is held in its attracted position during reversal of the polarity of the current supplied to the operatin winding of the device, and is slow to pick up when current is applied to the operating winding.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a View showing in front elevation one form of apparatus embodying my invention. Fig. 2 is a diagrammatic view showing one arrangement of circuits for the control of the apparatus shown in Fig. 1. Fig. 3 is a diagrammatic view showing another arrangement of circuits for the control of the apparatus shown in Fig.1.

Similar reference characters refer to similar parts in each of the views. I

Referring first to Fig. l, the apparatus in the form here shown, comprises an electromagnet M having an operating winding 3 and a secondary winding 4 in inductive relation to the operating winding. In actual practice this magnet comprises two cores each provided with an operating winding which windings are connected in series, and each also provided with a secondary winding which windings are likewise connected in series, but one of the cores with its associated windings is directly behind the other in the drawings. A neutral armature 7 pivotally mounted at the point 8, is controlled by the pole pieces 18 of the magnet M. The electromagnetic apparatus also involves the usual permanent magnet 5 which, together with the neutral magnet M, controls a polar armature 20. The operating winding 3 is supplied with current from a battery 29 through a pole-changer 30.

As shown in the drawings, the electromagnet embodying my invention is applied to a searchlight type of light signal, which signal is disclosed and claimed in an application for Letters Patent of the United States, filed by A. E. Dodd on October 6, 1932, Serial No. 636,526, for Light signals. Briefly described, the signal portion of the mechanism comprises a member 9 attached to the neutral armature '7 and provided with a stop screen R, as well as a recess 31, these parts being so arranged that the screen R or the recess 31 will be in front of a lamp L according as armature 7 is in the relased or the attracted position. A second member 10 is pivotally attached to the member 9 at point 11 and is movable between two stops 12 and 13 which are fixed to the member 9. The member 10 is provided with a proceed screen G and a caution screen Y, one or the other of which will register with the lamp L according as the member 10 is in its lower or its upper position, and provided, of course, that the recess 31 of member 9 is in front of the lamp. Member 10 is operated by the polar armature 20 through the medium of a hook 21 and a link 22 provided at its upper end with a hook 22? Link 22 is restrained to move in a vertical direction by a guide 23 attached to the member 9.

The reference character K designates an auxiliary magnet having a winding 25. In actual practice this magnet will usually comprise two cores each provided with a winding, which windings are connected in series. pieces 26 which coact with an auxiliary armature 2'7 attached to neutral armature 7 by a bar 28. The parts are so arranged that when the armature '7 is closed and magnet K is energized, the armature '7 will be held in its attracted position. The apparatus also involves a second auxiliary magnet K comprising two parallel cores (only one of which is shown in the drawings), each core being provided with a winding 41 which windings are connected in series. This magnet has pole pieces 42 coacting with the armature 27 in such manner that when the neutral armature 7 is in the released position and magnet K is energized, it will hold the armature '7 in such position. The circuits for magnets K and K are controlled by a front contact 4040 and a back contact 4040 operated by the neutral armature 7. When the neutral armature 7 is in its attracted position, the front contact ill--40 is closed and winding 25 of magnet K is then connected with the secondary winding 4 of the magnet M. When the neutral armature 7 is in its released position back contact 40-40 is closed, and the winding 41 of auxiliary magnet K is then connected with the secondary winding 4.

The operation of the apparatus illustrated in Fig. 1 is as follows: When pole-changer 30 is in the position shown in the drawings, which I will assume to be its normal position, operating winding 3 is supplied with current of normal polarity, so that neutral armature 7 is in its attracted position and the polar armature 20 is in its normal position. If now the pole-changer 30 is reversed, thereby reversing the polarity of the current supplied to the winding 3, the polar armature Magnet K has pole v is of the light signal type shown in Fig. 1.

20 will be reversed, but the neutral armature 7 will be held in its attracted position by magnet K owing to the surge of current supplied to the winding of this magnet by the auxiliary winding 4. I will now assume that the neutral armature 7 is released, thereby connecting magnet K with winding 4, and that the operating winding 3 becomes energized. The surge of current which will then be supplied to magnet K will serve to hold armature 7 in the released position for an appreciable interval of time. so that this armature is slow to pick up when magnet M becomes energized.

Referring now to Fig. 2, the reference characters 35 and 36 designate the track rails of a stretch of railway track along which trafnc normally moves in the direction indicated by the arrow. These rails are divided by insulated joints 39 to form track sections, of which only one complete section is shown in the drawings. Each section is provided with the usual track circuit comprising a battery 37 and a track relay 38. Each section is also provided with a light signal of the type shown in Fig. 1, the only elements of this signal which are shown in Fig. 2 being the operating winding 3, the secondary winding 4 and the first auxiliary magnet 25. The operating winding 3 is provided with a circuit which includes contact 33 of track relay 38, and the pole-changer 30, which, as here shown, is operated by the neutral armature of the signal for the next section in advance. Furthermore, the circuit for the auxiliary magnet winding 25 includes a front contact 34 of the associated track relay 38 so that this circuit is open when the associated track section is occupied.

When a train enters the track section shown in Fig. 2, it will deenergize relay 38, thereby deenergizing the operating winding 3 of the associated signal and also opening at contact 34 the circuit for the auxiliary magnet winding 25. This destroys what would otherwise be a slow releasing characteristic of the apparatus and so insures that the signal will assume the stop indication without delay. When the train passes into the section next in advance, it may allow the track relay 38 for the section which the train is leaving to pick up before the track relay for the section which the train is entering becomes released. In this event, winding 3 for the signal in the rear will be momentarily energized, but due to the slow pick-up characteristic of the armature '7, this signal cannot be operated to momentarily flash the proceed indication during the change from the stop to the caution indication.

Referring to Fig. 3, the reference characters 43 and 44 designate the track rails of a stretch of railway track along which traffic may normally move in either direction. These rails are divided by means of insulated joints 39 to form track sections aP-b, bc, c-d, d,e and e-f. Each of these sections is provided with the usual track circuit comprising a battery 37 and a track relay designated by the reference character 38 with a distinguishing exponent.

Adjacent the point 0 are signals designated by the reference characters S and S and adjacent the point (1 are signals designated by the refer ence characters S and 5. Each of these signals Signals S and S govern westbound trafiic movements, that is, traflic movements from right to left as shown in the drawings, whereas signals S and S govern eastbound trafl'ic movements. v

The circuits for secondary winding 4 and auxiliary magnet windings 25 and 41 of signals S and S are exactly similar to those shown in Fig. 1. The circuits for the corresponding windings of signals S and S however, difier from the circuits shown in Fig. 1, as will be explained hereinafter. The operating winding 3 of each of the signals 5, S and S is provided with a circuit which includes a contact 33 of an associated track relay as in Fig. 2. The operating winding 3 of signal S is also provided with a circuit which includes a similar contact 33 of relay 38. The circuit for winding 3 of each of the signals S and S also includes a contact 48 of a track relay for a track section in advance of the section which is directly ahead of the corresponding signal. The circuit for winding 3 of each of the signals S and S is shown provided with a pole-changer 30 operated by the neutral armature of the next signal in advance as in Fig. 2, and is also supplied with current by a battery 29 as in Fig. 2.

In addition to the contacts shown in the circuit for operating winding 3 in Fig. 2, the circuits in Fig. 3 for windings 3 of signals S and S also include a back contact 46, operated by the mechanism of the next signal governing traffic movements in the opposite direction, which is connected in multiple with a front contact 45 of the track relay 38 for the first section in the rear of such opposing signal. The circuit for auxiliary winding 25 of each of the signals S and S does not include a contact of the associated track relay as in Fig. 2, butthe circuit for winding 41 of signal S includes a normal polar contact 47 which is operated by the mechanism of signal S All parts of the apparatus of Fig. 3 are shown in their normal condition, that is, all track relays 38 are energized, and winding 3 of each of the signals S is energized by current of normal polarity for causing the signal to display :1. proceed (green) indication. The circuit by which winding 3 of signal S is energized passes from a battery 29, through a front contact of pole-changer 30 of signal 5, contact 45 of relay 38, contact 33 of relay 38, winding 3 of signal S and a second front contact of pole-changer 30 of signal S back to battery 29. Winding 3 or" signal S is energized by a circuit which is similar to the circuit just traced for signal S The circuit for winding 3 of signal S includes contact 33 of relay 38 and contact 48 of relay 38 as well as other contacts not shown in the drawings. Winding 3 of signal S is energized by a circuit similar to that just mentioned for signal S If, with all parts thus in their normal condition, an eastbound train enters section a--b, deenergizing relay 38*, the circuit for winding 3 of signal S will be opened at contact 48 of relay 38", thus deenergizing winding 3 of signal S unless the circuit has previously been opened at some other point due to the approach of the eastbound train. The deenergization of winding 3 of signal S will cause this signal to display a stop indication, and will cause its pole-changer 30 to reverse the direction of flow of current to winding 3 of signal S Signal S will therefore display a caution indication.

When the train enters section b -c, relay 38 will become deenergized and open its contacts 33 and 34 in the circuits for windings 3 and 25 of signal S and will also open its contact 45 in the circuit traced for winding 3 of signal With winding 3 of signal S deenergized, signal S will display a stop indication.

When the train enters section c-d, relay 38 will become deenergized, opening its contact 33 in the circuit for winding 3 of signal S and opening its contact 33 in the circuit for winding 3 of signal S which is, however, already open at contact 45 of relay 38 as previously pointed out. Upon the deenergization of winding 3 of signal S winding 4 of this signal will produce a surge of current, which will flow through contact 40--40 of signal S and winding of this signal, tending to retain armature '7, shown in Fig. 1, in its attracted position. The mechanism of signal S is therefore slow releasing under this condition of train operation.

As the train proceeds further and enters section d-e, relay 38 will become deenergized, causing signal S to indicate stop, and opening contact 45 in the circuit for winding 3 of signal S The deenergization of winding 3 of signal S causes its pole-changer to be reversed in the circuit for winding 3 of signal S When the train leaves section de, permitting relay 38 to become energized, winding 3 of signal S will become energized by current of reverse polarity. Signal S will therefore display the caution indication.

When the train has proceeded far enough in the eastbound direction to permit winding 3 of signal S to again become energized, pole-changer 30 of this signal will be operated to its normal position, causing current of normal polarity to be supplied to winding 3 of signal S which will then display the proceed indication.

If an eastbound train moving through the stretch of track shown in the drawings as just described were so short and moved so quickly past the insulated joints at point it that relay 38 would close its front contact 33 before relay 38 could release, the normal energizing circuit for winding 3 of signal S would be completed for a brief period of time through contact 45 of relay 38 At this time, however, winding 4 of signal S on account of the energization of winding 3 of this signal, will produce a surge of current through contact 40-40 of signal S polar contact 4'7 of this signal, and its Winding 41, which will tend to retain armature 7, shown in Fig. 1, in its deenergized position, thus making the mechanism of signal S slow to pick up. This slow pick-up feature of signal S will therefore prevent signal S from falsely displaying the proceed indication during the interval between the closing of contact 33 of relay 38 and the dropping of contact of relay 38 The operation of the apparatus for a westbound train movement is similar to that just described for an eastbound train movement. The circuit for winding 41 of signal S however, does not include a polar contact such as contact 4'7 which is shown in the circuit for winding 41 of signal S I will now assume that an eastbound train is approaching signal S and that a westbound train is approaching signal S the eastbound train causing winding 3 of signal S to be deenergized and the westbound train causing winding 3 of signal S to be deenergized. Windings 3 of signals S and S are therefore energized in the reverse direction. I will further assume that the westbound train enters section d-e at the same instant that the eastbound train enters section bc.

Relays 38 and 38 will, therefore, permit their front contacts 45 to open at the same instant. This will cause windings 3 of signals S and S to become deenergized at the same instant. Winding 4 of each of these signals will cause a surge of current to flow through its contact 4040 to its winding 25, and hence the mechanism for each of these signals will be slow releasing.

Upon the closing of back contact 46 of signal S a reverse energizing circuit will be completed for winding 3 of signal S which is exactly the same as the energizing circuit previously described for this signal except that it includes contact 46 of signal S instead of contact 45 of relay 38 A similar reverse energizing circuit will at the same instant become closed for winding 3 of signal S through contact 46 of signal S On account of winding 3 of signal S having been energized in the reverse direction previous to its deenergization by the opening of contact 45 of relay 38 contact 47 of signal S is open, and hence when the circuit for winding 3 of signal S is closed through back contact 46 of signal S there will be no surge of current through winding 41 of signal S The mechanism of signal S will, therefore, be quick to pick up whereas the mechanism of signal S will be slow to pick up since a surge of current will be supplied by winding 4 of signal S through its contact 4040 to its winding 41. Hence the mechanism of signal S will open its contact 46 in the circuit for signal S whereas contact 46 of signal S will remain closed in the circuit for winding 3 of signal S Signal S will, therefore, display the caution indication whereas signal S will display the stop indication.

Preference is thus given to an eastbound train in the event of an eastbound train entering section bc at exactly the same instant that a westbound train enters section de. This will prevent the alternate clearing of signals S and S under such a condition of train operation.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Electromagnetic apparatus comprising an electromagnet having an operating winding and a secondary winding in inductive relation to the operating winding, an armature controlled by said electromagnet, a first auxiliary magnet arranged when energized to hold said armature closed, a second auxiliary magnet arranged when energized to hold said armature open, and means including a contact operated by said armature for connecting said secondary winding with said first or said second auxiliary magnet according as said armature is in the closed or the open position, whereby the armature remains closed during reversal of the polarity of the current supplied to said operating winding and is slow to pick up when current is applied to the operating winding.

2. Electromagnet apparatus comprising a direct current electromagnet, an armature controlled thereby, a first auxiliary magnet effective when energized to hold said armature closed, a second auxiliary magnet effective when energized to hold said armature open, and means for momentarily energizing said first auxiliary magnet when the polarity of the current supplied to said electromagnet is reversed and for momentarily energizing said second auxiliary magnet when current is applied to said electromagnet, whereby said armature is slow to pick up and remains closed during reversal of the polarity of the current supplied to the electromagnet.

PAUL H. CRAGO. 

